Workpiece feeding device



Oct. 14, 1958 A. BuRcKHARbT EI'AL 2,856,187

WORKPIECE FEEDING DEVICE 4 Sheets-Sheet 1 Filed Nov. 18, 1955 BRUCE E.

ATTORNEY Oct. 14, 1958 A. BURCKHARDT rrm. 2,856,187

WORKPIECE FEEDING DEVICE 4 Sheets-Sheet 2 Filed Nov. 18, 1955 \NVENTOR HLFRED BURCKHARDT ATTORNEY I Oct. 14, 1958 A. BURCKHARDT ETAL 2,856,187

WORKPIECE FEEDING DEVICE 4 Sheets-Sheet 3 Filed Nov. 18, 1955 \NVENTOR HLFRED BURCKl-IARDT apucz WILLIAMS ATTORNEY Oct. 14, 1958 A. BURCKHARDT EI'AL 2,856,187

WORKPIECE FEEDING DEVICE 4 Sheets-Sheet 4 Filed Nov. 18, 1955 I PHOTO CELL United States Patent WORKPIECE FEEDING DEVICE Alfred Bnrclkhardt, Stamford, Conn., and Bruce E. Williams, Elmsford, N. Y., assignors to Pitney-Bowes, Inc., Stamford, Conn, a corporation of Delaware Application November 18, 1955, Serial No. 547,645 4 Claims. (Cl. 271-26) This invention relates to devices for feeding workpieces one at a time from a stack, and more particularly to the feeding of workpieces, such as paper sheets, letter mail and the like, on which some operation is to be performed.

In feeding workpieces from a stack, when the workpieces are of substantially the same length in the direction of feed, suitable timing mechanism may be provided to start the terminal workpiece of the stack forward to a position where it can be gripped by continuously operating feed mechanism so as to be drawn off the stack to receive or to effect some operation. Such timing mechanism may include suitable gearing arranged to cause a space or gap to be provided between subsequent workpieces in the continuous flow of the latter from the stack.

However, where the workpieces are of varying length in the direction of feed, such as when feeding letters, the mechanism will not operate as intended, and if an attempt is made to use it, the longer workpieces would overlap in the flow from the stack and the gap between the shorter workpieces would be longer than desired.

An object of the present invention is to provide a feeding device for removing one workpiece at a time from the stack having various lengths in the direction of feed and in such manner that a gap of predetermined length is left between successive workpieces in the flow thereof from the stack.

This is accomplished, in the form of the invention illustrated herein as exemplary thereof, by providing means under the control of a workpiece in the feed path for causing the feeding means to take the next workpiece from the stack.

In the specific embodiment of the invention illustrated and described herein, the means controlled by the advancing workpiece includes a source of light and a light-responsive device, such as a photocell, arranged on opposite sides of the feed path so that when the trailing edge of a workpiece passes a predetermined point, the means for feeding the next workpiece from the stack is rendered operative. Further, when the aforesaid workpiece reaches said predetermined point in the feed path, the light beam is interrupted to render the feeding means temporarily inoperative. In this way, the second workpiece in the stack, for instance, will not start to advance until the trailing edge of the first workpiece has passed a predetermined point in the feed path regardless of its length in the direction of feed, thus establishing a predetermined gap between the trailing edge of the first workpiece and the leading edge of the second workpiece.

In the broader aspects of the invention, any suitable means for starting the advance of any terminal workpiece in a stack may be employed. However, since the feeding means should act immediately upon the first workpiece reaching a predetermined point, it has been found advantageous to employ as feeding means a constantly moving feeding device adjacent to but normally ineffective upon the terminal workpiece, but which can be made effective by simple and quick-acting means con- 2 trolled by the means responsive to the advancing workpiece.

In the embodiment of the invention shown herein as exemplary thereof, the constantly operating member for advancing the workpieces is in the form of a perforated belt traveling next to the terminal workpiece in the stack, but normally having insufficient frictional feeding contact therewith to advance the workpiece. The means for rendering the feeding means operative on the terminal workpiece at the proper time comprises suctionproducing means having, for instance, a cup engaging the opposite side of the belt whereby the terminal workpiece is sucked against the belt and caused to have gripping engagement therewith so as to be carried forward thereby. The suction means is connected to a suitable suction-producing device, but between the latter and the suction cup there is provided valve means electrically operated in response to the photocell so that when the feed device is to be operative the suction is applied to the suction cup and when it is to be temporarily inoperative the suction cup is connected to the atmosphere.

Because of the quick action of the valve means and the resulting quick creating or destruction of the vacuum under the control of the advancing workpiece and the photoelectric means, the timing of the advance of each subsequent workpiece from the stack can be accurately controlled and uniform gaps provided between successive workpieces regardless of the length of the workpieces in the direction of feed.

This is an important advantage in feeding workpieces, particularly sheets of paper and envelopes varying in length, since the number of pieces which can be fed by the device per hour may be maintained at practical limits without the loss of time which would result if the device were timed to advance the workpieces, without overlapping, according to the workpiece which is longest in the direction of feed.

Other features and advantages will hereinafter appear.

Fig. l is a plan, partly in section, showing the feeding device of the present invention and a stacking machine;

Fig. 2 is a vertical section taken substantially on the line 22 of Fig. 1;

Fig. 3 is a vertical section taken on the line 33 of Fig. 1;

Figs. 4-7 inclusive are diagrammatic views indicating positions of the parts during successive stages in the operation of the device;

Fig. 8 is a schematic diagram of the electrical components of the device; and

Fig. 9 is a detail view showing the belt and its relation to the suction cup.

Referring to the illustrated embodiment of my inven tion, there is shown in Fig. 1, a separating and feeding device indicated generally by the reference numeral 10, and a stacker, generally indicated by the reference numeral 11. A mechanism (not shown) for operation by, or for operating on, the workpieces being fed can be positioned between the broken lines A and B separating the feeding device 10 and the stacker 11. Such a mechanism may include counting or printing devices or a postage canceling device if the workpieces are envelopes, or a scanning device if the sheets carry indicia to be sensed or recorded.

In the feeding device 10, a stack indicated by the reference numeral 12 of vertically arranged workpieces W is positioned in a piece feeding hopper 13. The workpieces, which in the present instance represent letters, are shown as varying in length and thickness. The hopper 13 has a front vertical wall 14 against which the leading edges W of the workpieces W forming the stack 12 are positioned. The bottom horizontal edges of the pieces are supported on a fiat base plate 15 of the hopper 13. A

carriage 16 forming part of the hopper has a vertical plate 17 which engages the face of the terminal workpiece in the stack and a horizontal plate 18 which is provided with rollers 19 riding on tracks 20. The carriage 16 may be yieldingly urged, as by a spring (not shown) or a weight and cord (not shown) or by hand, toward the separating and feeding device to advance the stack as successive workpieces are fed from the stack.

The feeding device as shown comprises a flat, endless belt 21 having teeth 22 along its longitudinal edges on its inner surface. The belt 21 is supported and driven by toothed pulleys 23 and 24. An electric motor 25 drives the pulleys 23 and 24 and the belt 21 by means of a belt 26 connected between the pulley 23 and the motor 25.

Means, generally indicated by the reference numeral 27, is provided for restricting the passage of the workpieces from the stack 12 into the feed path to only a single piece at a time. The restricting means consists of abutments 28 mounted on a link 29. The link 29, by means of springs 30, is spring urged towards the belt 21. A manual adjustment knob 31 is provided to control the bias and as a quick withdrawal of the abutments 28 should an excessively thick workpiece cause the feeding means to cease functioning. This restricting means is more fully illustrated and described in Patent No. 2,635,874, granted on April 21, 1953, to W. T. La Bore.

The feeding means also includes a continuously driven roller 32 and a cooperating yieldingly mounted roller 33 to advance the workpieces after they are fed from the stack by the belt 21. The peripheral speed of the roller 32 is at least equal and preferably greater than the speed of the belt 21. The feed rollers 32 and 33 are located in the path of feed of the workpiece as it advances off the stack.

The stacker 11, is located in the path of travel of the workpieces to receive the latter after they have been cooperated with by means of the devices located between the stack 12 and the stacker 11 from the feeding device 10 and has an endless moving friction belt 37 supported and driven by pulleys 38. T e stacker 11, moreover, has a vertical end wall 39 and a flat base plate 461, the plate 40 being provided with rollers 41 operating on tracks 42 to facilitate movement of the plate. A vertical guide 43 mounted on the plate 40 etfectuates and maintains the workpieces in a stacked relationship.

With the above-disclosed parts, there is insuificient frictional contact between the belt 21 and the adjacent workpiece 12a of the stack to cause the workpiece to be moved by the belt from the stack and past the restricting means 27. In order to increase the grip of the workpiece b! the belt, there is provided a vacuum apparatus, generally indicated by the reference numeral 45, and in which the initiation and duration of the vacuum is controlled by the position in the feed path of a prior fed workpiece. This apparatus includes suction means which operates through apertures 46 in the belt 21 to create a suction effect between the belt and the terminal workpiece. The apertures 46, as shown in Fig. 9, are spaced equal distances throughout the full length of the belt in order that the suction can be created at any point on the belt. A vacuum cup 47 positioned between the pulleys 23 and 24 abuts the inner surface of the belt between the two edge portions thereof carrying the teeth 22 and in alignment with the apertures 46. A pipe 48 is connected between a normally closed solenoid-operated vacuum valve 49 and the cup 47. Another pipe 50 leads from the valve 49 and is connected to a suitable vacuum source (not shown). Positionedin the pipe 48 is a normally closed solenoidoperated bleed valve 51 having a bleed port 52 for venting the vacuum to the atmosphere upon operation of the valve.

In order to control the operation of valves by the location of the prior fed workpiece in the feed path, there is provided a light source 53 and a photocell 54. The source 53 and cell 54 are positioned on opposite sides of the feed path so that a workpiece in the path can interrupt the light beam to the cell with its leading edge and maintain the beam interruption until the trailing edge of the workpiece has passed. Shown schematically in Fig. 8 the photocell 54 is connected in series with an ampliher 55 and a relay 57, while lines 56 connect the circuit to a source of electrical energy. The relay 57 has a switch arm 58 operable between two fixed contacts 59 and 60 and a line 61 connects the switch arm 58 to one side of the source of energy. Contact 59 through lines 62 and 63 connects the solenoid valve 49 to the other side of the source, while contact 60, lines 64 and 65 connect the bleed valve 51 to the line 63, the other side of the source. The vacuum solenoid 49 is energized whenever the light beam strikes the photocell and causes contact 59 and switch arm 58 to be in electrical engagement. Alternatively, when the light beam is interrupted and fails to strike the photocell 54, the relay 57 then being non-energized, the switch arm 58 will be in engagement with contact 60 and consequently energizes the bleed valve 51. The switch arm 58 is normally biased or spring urged toward contact 60.

The operation of the feeding device is as follows:

As shown diagrammatically in Figs. 4-7, the stack 12 is positioned with its terminal workpiece W in engagement with the belt 21. When the suction valve 49 opens with the bleed valve 51 closed, a gripping contact occurs between the workpiece W and the belt 21 causing the belt to grip the workpiece and carry it from the stack past the restricting means 27. In Fig. 5 the leading edge W of the workpiece has interrupted the light beam to the photocell 54, closing the vacuum valve 49 and opening the bleed valve 51. The movement given the workpiece by the belt 21 is such as to create sufiicient momentum to carry the workpiece from the belt to the rollers 32 and 33, even after the suction has been instantaneously destroyed. As shown in Fig. 6, the light beam is interrupted and the bleed valve 51 remains open until the workpiece reaches a location in the feed path at which the trailing edge W is just beyond the light beam. When the light beam strikes the photocell 54, suction is again applied through the apertures 46 in the belt, increasing the gripping contact between the subsequent terminal workpiece and the belt 21 to carry the workpiece beyond the restricting means 27 to repeat the feeding and separating operation. The position of the prior fed workpiece W controls when the subsequent workpiece W is to be started from the stack along the path of travel of the workpiece. The space between the trailing edge W" of the workpiece W and the leading edge of the workpiece W is substantially the same as between like parts of all the other adjacent workpieces as they pass through the feed path, irrespective of the dimension of the workpieces coinciding with the feed path. In the specific embodiment disclosed the minimum length of a workpiece is the distance between a line passing through the axis of the rollers 32 and 33 and the further inner surface 47a of the vacuum cup 47.

Although, in the Figures 1 and 4-7 inclusive, the stacker 11 has been shown as directly receiving the workpiece from the feeding and separating device without any other work performing devices in between, it will be understood that some type of work performing devices will be interposed between the feeding device 10 and the stacker 11.

From the above it will be seen that the separating and feeding device of the present invention takes the workpiecessingly from the stack and moves them along a feed path in Which means for causing the feed means to take a subsequent workpiece from the stack is controlled by a previous workpiece in the work path.

In the specific embodiment of the invention shown,the advancement of the subsequent workpieces is controlled through the medium of the photocell actuated by the light beam which is interrupted by the workpiece passing therethrough. In order that the feed means may instantaneously operate to separate and advance a workpiece, the

feeding means is constantly moving in work-separating and advancing direction but is normally ineffective. It is made operative to advance the work instantly in response to the operations of the photocell, and hence no time is lost and the optimum spacing between the trailing edge of one workpiece and the leading edge of the next is uniformly obtained. These advantageous results are ob tained Without stopping the advancing movement of the workpieces which, when the preferred form of the device of the present invention is employed, flow in a continuous stream from the stacker to the mechanism which is to be controlled by, or which is to operate on, the workpiece.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

What is claimed is:

l. A device for separating and feeding workpieces which vary in length in the direction of feed singly along a feed path with a substantially constant space between each successive pair of adjacent workpieces comprising means for storing a stack of workpieces, an endless belt having apertures throughout its length, means for traveling the belt, the belt being positioned to have one side engage the terminal workpiece in the stack, a vacuum cup engaging the other side of the belt and creating a suction through the apertures for causing the terminal workpiece to be gripped and advanced by the belt, means including valve means connected to the vacuum cup to create or destroy vacuum in the cup to cause the belt to grip or release a workpiece, and means including photoelectric means associated with the valve means and responsive to the location of the advancing workpiece for controlling the operation of the valve means.

2. The invention as defined in claim 1 in which the photoelectric means includes a light source and a photocell positioned on opposite sides of the feed path whereby the light beam therebetween may be interrupted by a workpiece in the feed path.

3. A sheet separating and feeding mechanism comprising a feeding device including a continuously perforated endless belt defining a feed path by one surface thereof, and a hopper for supporting a plurality of envelopes on edge in a stack formation and for presenting at least half of the surface length of each of the terminal envelopes to the outer Surface of the belt portion of the feeding device, whereby one envelope at a time is fed. along the path by the feeding device from the stack, said feeding device also including friction means for restricting the passing of more than one envelope at a time at a point along the feed path, an elongate cup engaging the inner surface of the belt opposite the terminal envelope, a valve controlled vacuum source connected with the cup for increasing the frictional force between the terminal envelope and the belt, solenoid control means for said valve, and electrical means controlled by the location of a prior fed envelope in the feed path to energize the solenoid and thereby cause the belt to move the subsequent terminal envelope into the feed path from the stack in the hopper.

4. A device for separating and feeding variable length workpieces singly along a feed path with a substantially constant space between each successive pair of adjacent workpieces comprising means for presenting a stack of workpieces on edge, an endless belt having apertures throughout its length, means for traveling the belt, the belt being positioned to have a substantial portion of one surface thereof engage substantially the entire length of the face of the terminal workpiece in the stack position, a stationary vacuum cup engaging the inner surface of the belt opposite the apertures and creating a suction through a plurality of apertures for causing the terminal workpiece to be drawn to and advanced by the belt, means including a solenoid actuated valve connected to the vacuum cup to create or destroy vacuum in the cup to cause the belt to attract or release a workpiece, and electrically operative means associated with the solenoid actuated valve and responsive to the location of the advancing workpiece for controlling the operation of the valve means.

References Cited in the file of this patent UNITED STATES PATENTS 1,469,515 Kelly *Oct. 2, 1923 r 1,624,787 Hallstream Apr. 12, 1927 2,171,362 Gulliksen Aug. 29, 1939 2,680,614 Gibson JuneS, 1954 

